Idea 1: A sword that can change various physical and chemical properties of materials it comes into contact with, such as color, size, temperature, solid/liquid/gas phase, etc. Note: This is not a self insert. The name for the SCP, "Delta Blade", refers to the fact that in science and mathematics, Δ (or delta) is the symbol that denotes change.

Idea 2: Not an SCP, but a post for the Extranormal Events log. All showers, sinks, toilets, waterfalls, waterslides, etc. in the state of ██████ start flowing backwards (from source into the fixture)

Idea 3: A language tutoring center in NYC. Any who enter the building leave it knowing one language that they never knew how to speak, and forget one language that they did know how to speak. Discovery could be attributed to the rapid increase in non-english-speakers in New York.

I personally find this a really interesting idea (because, from my knowledge, it is original), but I think your first step is to first set in the rules. Does it change a random property by a random value when it comes in contact with the object? Wouldn't that make its everyday use, as it would come in contact with air, potentially dangerous? Another thing to keep in mind is its origin story. I would personally not go for the old relic cliche: What if the Δ blade is just a random Chef's knife, of an otherwise normal brand? I think that would make for an interesting story, as it adds this almost humorous contrast.

I haven't really decided if I find it interesting or not, but instead of making it a state-wide event, which would be far too noticeable, I am more of a fan of the idea of it happening in a random town in the middle of nowhere. Almost becomes an urban legend.

Sadly, I don't have much feedback for the third one. One interesting thing I thought of while writing this was what if the Foundation enlisted the center's help to decode texts written in unknown languages (after all, subjects like SCP-073 aren't always willing to help).

The blade simply changing is a sort of generic concept. Perhaps the blade adapts to its surroundings, like an organism, to become optimal for its usage? What is the initial purpose of the knife, and how was it made or who made it? A chef’s knife is a good start, but perhaps it is only found like that because that was what it was used for?

This phenomenon feels a bit empty in terms of being an idea. Why must this be contained? How exactly does a faucet “flow backward”? Is this some sort of portal or gateway, or is this the result of another entity? Again, making it statewide just makes this idea another “headache for the Foundation” SCP. Making it more localized, perhaps even down to one faucet at a time, in a pattern, would help.

Personally, this is your most usable idea, since it opens up a lot of room for development. A thing to consider is making it teach arcane, demonic, or non-existent languages, making this a sort of nexus of languages? What makes this building different from any other, or is it a normal building? Salt_Pillar had a good idea, but the sheer randomness would make it a pain. Perhaps specific rooms cause different languages?

Sorry if I'm spamming but Greyve's addition to the third idea does open up a lot of possibilities, eg:

The Institute is a GoI of sorts. It can "build" rooms that can teach a person a language and maybe it has more than one location worldwide. Maybe it even rotates through different locations, or its rooms do.

Maybe there are a plethora of rooms to be accessed, but that can only be done through a specific ritual or item.

What specifically do you like about it? What about the others? Why did you like/dislike those?

I feel like you could write in some pretty interesting experiment or interview logs.

How so? What about those logs would be interesting? What kind of material would the author need to put in those logs to attract a reader's attention?

If you're going to try giving feedback in the forums, try to at least respond to specifics rather than posting a generic response that could be interpreted as relating to any number of drafts. Furthermore, the point of the forums is to help the author improve their work. If you don't have anything to say in that regard, let someone else handle making the first post.